My SOHC 6G72 motor made 220 fwhp before it was even broken-in, at 1,300 ft. above sea level, ambient temperature of 90 degrees. This setup was deliberately designed to be driven comfortably at slow street speeds or at high road speed, not the track.
Had I wanted more power for purely racing purposes, I could have made more modifications. I discussed this at length with David Thomas at Racing Performance Works (their six-pack throttle system and much more aggressive camshafts) several years ago.
Here's some more on his build. He usually deletes his posts on the forum. His website used to be 3000gt-sohc.com but now its gone.
How to get 200 crank HP out of a n/a 3.0? - Page 2 - Turbo Dodge Forums : Turbo Dodge Forum for Turbo Mopars, Shelbys, Dodge Daytona, Dodge SRT-4, Chrysler PT Cruiser, Omni and more!
Here's a quote I found from sunmind
I respectfully suggest that my vehicle is producing at least the same or even more than Eric's DOHC. Mine dynoed at 220 immediately the engine was built, at 2,000 feet with air temperatures close to 90 degrees.
The engine pulls much more strongly now, after 4,000 miles. I use it once a week to run errands and keep it in good shape. My daily driver is a 300+ hp (3.5 liter) Infiniti and I do not feel as though the 3000GT is a slug by comparison.
Notice the Est next to it.. I've been playing with the timing with a few knowledgeable members help, TT guys too... and the car is responding very well...after all that's what made most of my power in the first place was Timing then just throwing the right mods at it... Dyno is scheduled soon. aiming for 220whp